[mips] Changed the way expressions in instructions are printed to support different kinds of expressions.

[s.egerton]

Summary

This added support for printing MCUnaryExpr as well as different kinds of
MCBinaryExpr.

[dsanders]

Hi,

As explained at D13592, I'd prefer not to commit this since it further breaks encapsulation of the MCExpr hierarchy. Instead, we should try to get the existing code into our MipsMCExpr. This will be difficult (chiefly because we appear to implement things like %hi as both an operator and part of the symbol which will also need fixing) but fixing the encapsulation will be cleaner overall.

lib/Target/Mips/InstPrinter/MipsInstPrinter.cpp

void MipsInstPrinter::printInst(const MCInst *MI, raw_ostream &O,
   case Mips::RDHWR:
   case Mips::RDHWR64:
     O << "\n\t.set\tpop";
   }
 }
 
 static void printExpr(const MCExpr *Expr, const MCAsmInfo *MAI,
                       raw_ostream &OS) {
-  int Offset = 0;
   const MCSymbolRefExpr *SRE;
+  const MCBinaryExpr *BE;
 
-  if (const MCBinaryExpr *BE = dyn_cast<MCBinaryExpr>(Expr)) {
+  int64_t Absolute;
+  if (Expr->evaluateAsAbsolute(Absolute)) {
+    OS << Absolute;
+    return;
+  }
+
+  if ((BE = dyn_cast<MCBinaryExpr>(Expr))) {
     SRE = dyn_cast<MCSymbolRefExpr>(BE->getLHS());
-    const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(BE->getRHS());
-    assert(SRE && CE && "Binary expression must be sym+const.");
-    Offset = CE->getValue();
+    if (!SRE)
+      printExpr(BE->getLHS(), MAI, OS);
+  } else if (const MCUnaryExpr *UE = dyn_cast<MCUnaryExpr>(Expr)) {
+    switch (UE->getOpcode()) {
+    default:
+      llvm_unreachable("Invalid unary opcode");
+    case MCUnaryExpr::Opcode::Minus:
+      OS << '-';
+      break;
+    case MCUnaryExpr::Opcode::Not:
+      OS << '~';
+      break;
+    case MCUnaryExpr::Opcode::Plus:
+      OS << '+';
+      break;
+    case MCUnaryExpr::Opcode::LNot:
+      llvm_unreachable("Unsupported unary opcode in this context");
+    }
+    printExpr(UE->getSubExpr(), MAI, OS);
+    return;
   } else if (const MipsMCExpr *ME = dyn_cast<MipsMCExpr>(Expr)) {
     ME->print(OS, MAI);
     return;
+  } else if ((SRE = cast<MCSymbolRefExpr>(Expr))) {
+    // Symbols will be printed later
   } else
-    SRE = cast<MCSymbolRefExpr>(Expr);
+    llvm_unreachable("Unknown expression type");
 
-  MCSymbolRefExpr::VariantKind Kind = SRE->getKind();
+  MCSymbolRefExpr::VariantKind Kind;
+  if (SRE) {
+    Kind = SRE->getKind();
 
     switch (Kind) {
     default:                                 llvm_unreachable("Invalid kind!");
     case MCSymbolRefExpr::VK_None:           break;
     case MCSymbolRefExpr::VK_Mips_GPREL:     OS << "%gp_rel("; break;
     case MCSymbolRefExpr::VK_Mips_GOT_CALL:  OS << "%call16("; break;
     case MCSymbolRefExpr::VK_Mips_GOT16:     OS << "%got(";    break;
     case MCSymbolRefExpr::VK_Mips_GOT:       OS << "%got(";    break;
     case MCSymbolRefExpr::VK_Mips_ABS_HI:    OS << "%hi(";     break;
     case MCSymbolRefExpr::VK_Mips_ABS_LO:    OS << "%lo(";     break;
     case MCSymbolRefExpr::VK_Mips_TLSGD:     OS << "%tlsgd(";  break;
     case MCSymbolRefExpr::VK_Mips_TLSLDM:    OS << "%tlsldm(";  break;
     case MCSymbolRefExpr::VK_Mips_DTPREL_HI: OS << "%dtprel_hi(";  break;
     case MCSymbolRefExpr::VK_Mips_DTPREL_LO: OS << "%dtprel_lo(";  break;
     case MCSymbolRefExpr::VK_Mips_GOTTPREL:  OS << "%gottprel("; break;
     case MCSymbolRefExpr::VK_Mips_TPREL_HI:  OS << "%tprel_hi("; break;
     case MCSymbolRefExpr::VK_Mips_TPREL_LO:  OS << "%tprel_lo("; break;
     case MCSymbolRefExpr::VK_Mips_GPOFF_HI:  OS << "%hi(%neg(%gp_rel("; break;
     case MCSymbolRefExpr::VK_Mips_GPOFF_LO:  OS << "%lo(%neg(%gp_rel("; break;
     case MCSymbolRefExpr::VK_Mips_GOT_DISP:  OS << "%got_disp("; break;
     case MCSymbolRefExpr::VK_Mips_GOT_PAGE:  OS << "%got_page("; break;
     case MCSymbolRefExpr::VK_Mips_GOT_OFST:  OS << "%got_ofst("; break;
     case MCSymbolRefExpr::VK_Mips_HIGHER:    OS << "%higher("; break;
     case MCSymbolRefExpr::VK_Mips_HIGHEST:   OS << "%highest("; break;
     case MCSymbolRefExpr::VK_Mips_GOT_HI16:  OS << "%got_hi("; break;
     case MCSymbolRefExpr::VK_Mips_GOT_LO16:  OS << "%got_lo("; break;
     case MCSymbolRefExpr::VK_Mips_CALL_HI16: OS << "%call_hi("; break;
     case MCSymbolRefExpr::VK_Mips_CALL_LO16: OS << "%call_lo("; break;
     case MCSymbolRefExpr::VK_Mips_PCREL_HI16: OS << "%pcrel_hi("; break;
     case MCSymbolRefExpr::VK_Mips_PCREL_LO16: OS << "%pcrel_lo("; break;
     }
-
     SRE->getSymbol().print(OS, MAI);
+  }
 
-  if (Offset) {
-    if (Offset > 0)
+  if (BE) {
+    switch (BE->getOpcode()) {
+    default:
+      llvm_unreachable("Unknown binary opcode");
+    case MCBinaryExpr::Opcode::Add:
       OS << '+';
-    OS << Offset;
+      break;
+    case MCBinaryExpr::Opcode::Sub:
+      OS << '-';
+      break;
+    case MCBinaryExpr::Opcode::Div:
+      OS << '/';
+      break;
+    case MCBinaryExpr::Opcode::Mul:
+      OS << '*';
+      break;
+    case MCBinaryExpr::Opcode::Mod:
+      OS << '%';
+      break;
+    case MCBinaryExpr::Opcode::Shl:
+      OS << "<<";
+      break;
+    case MCBinaryExpr::Opcode::AShr:
+      OS << ">>";
+      break;
+    case MCBinaryExpr::Opcode::LShr:
+      OS << ">>>";
+      break;
+    case MCBinaryExpr::Opcode::And:
+    case MCBinaryExpr::Opcode::EQ:
+    case MCBinaryExpr::Opcode::GT:
+    case MCBinaryExpr::Opcode::GTE:
+    case MCBinaryExpr::Opcode::LAnd:
+    case MCBinaryExpr::Opcode::LOr:
+    case MCBinaryExpr::Opcode::LT:
+    case MCBinaryExpr::Opcode::LTE:
+    case MCBinaryExpr::Opcode::NE:
+    case MCBinaryExpr::Opcode::Or:
+    case MCBinaryExpr::Opcode::Xor:
+      llvm_unreachable("Unsupported binary opcode in this context");
+    }
+    printExpr(BE->getRHS(), MAI, OS);
   }
 
   if ((Kind == MCSymbolRefExpr::VK_Mips_GPOFF_HI) ||
       (Kind == MCSymbolRefExpr::VK_Mips_GPOFF_LO))
     OS << ")))";
   else if (Kind != MCSymbolRefExpr::VK_None)
     OS << ')';
 }